Rotary kiln the size of the original stone used often for 10 ~ 40mm, as it passes through the furnace during the furnace, often pink and powder of small particles and small particles, and large particles and together with the large particles each hierarchical segregation. Generally, in the industrial production of this phenomenon is inevitable, especially when more than 15% of dust, aggravated. Granularity caused its partial assembly firing in mutual differences, deserve specific attention.